[Ultrastructural demonstration of rabbit heart myocyte metabolism during fasting].

Thirty mature rabbits were completely deprived of food but water ad libitum for 10 days, then half of the animals were decapitated. The remaining animals were sacrificed 10 days after a sound diet. Histological, histochemical (estimation of glycogen, lipids, acid glycosamineglicans) and electron microscopic investigation of the myocardium was carried out. Degenerative and necrobiotic alterations were not revealed in muscular cells of the heart. At fasting accumulation of lipids and glycogen in the cardiac myocytes was evident. In fasting animals ultrastructure of the muscular cells of the heart demonstrated a certain decrease in synthetic processes. After a 10-day sound diet, the cardiac myocytes were actively involved into the process of intracellular regeneration. Increased lipid content in the rabbit myocardium, occurring at fasting, is connected with the necessity to provide the heart with an effective energy substrate required to preserve its contractile function and in this way adaptive-compensatory processes are demonstrated.